I’ve done some research about local data saving using ionic. I found that it is recommended to use localstorage. I know that localstorage is for browsers, but how are the saved data as localstorage turned for Android and iOS applications after building the app from a web app to a platform app.

ionic applications are hybrid, meaning that they are neither truly native (because all layout rendering is done via web views instead of the platform’s native UI framework) nor purely web-based (because they are not just web apps, but are packaged as apps for distribution and have access to native device APIs). As it uses in-app browser to run app, you can use localstorage or webSql.